Top: CD4 responses to protease inhibitor (PI) treatment. Individual counts are given at baseline, at 6-8, and at 12-16 weeks. (A) Non-responders. (B) Biphasic responders: an initial increase is followed by a return back to initial values. (C) Sustained responders: after an initial increase, a higher level is reached at 16 weeks and maintained for a prolonged period (up to 52 weeks). Bottom: Outcome with respect to CMVR: R=recurrence; S=smouldering; C=completely inactive. Patient 13, whose retinitis remained smouldering, was non-compliant with respect to his PI and anti-CMV medications, and died after 16 weeks of follow up. Vitritis is indicated by an asterisk.